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Purpose:To analyze the anatomical characteristics of arch aneurysms and evaluate the anatomical feasibility of 4 next-generation stent-grafts with either branched or fenestrated configurations. Materials and Methods:A retrospective analysis was conducted of 213 patients (mean age 75.0±7.1 years; 179 men) with arch aneurysms treated using total arch replacement or zone 0 or 1 thoracic endovascular aortic repair (TEVAR) from 2007 to 2017 at 2 Japanese hospitals. Anatomical analyses were performed using the centerline of flow technique on a 3-dimensional workstation. The anatomical feasibility of the Zenith A-branch, TAG Thoracic Branch Endoprosthesis (TBE), Terumo Aortic Relay Plus Double Branched (DB), and fenestrated Najuta stent-grafts were evaluated based on the instructions for use (IFU). Results:The mean lengths from the sinotubular junction (STJ) to the innominate artery (IA) and from the IA to the left common carotid artery were 114.9±15.9 and 12.8±5.6 mm, respectively. The mean aortic diameters at the STJ and IA were 31.3±3.4 and 34.1±5.3 mm, respectively. In terms of feasibility, 5.2% of patients were within the Zenith A-branch IFU, 40.8% for the TAG TBE, 24.9% for the Relay Plus DB, and 13.6% for the Najuta. Significant (>50% circumference) thrombus/calcification at the sealing zone affected nearly half of the patients, but there is currently no standardized definition or evaluation method for “significant” thrombus/calcification. Conclusion:Only 5% to 41% of arch aneurysm patients are anatomically suitable for TEVAR using any one of the next-generation branched or fenestrated stent-grafts. Furthermore, a definitive method of evaluating the thrombus/calcification burden needs to be established in future IFU.

Although general anesthesia allows relief from stressors such as pain, discomfort, or anxiety for patients undergoing carotid endarterectomy, neurologic assessment is less reliable than under local anesthesia. We describe a unique anesthetic management strategy for carotid endarterectomy patients incorporating the advantages of both general and local anesthesia. The technique allows thorough assessment of neurologic function during carotid cross-clamping by intraoperative wake-up, and guarantees airway management by tracheal intubation.

Left heart bypass reduces the risk of ischemic complications during the repair of extensive thoracoabdominal aortic aneurysms. This prospective study compared the performance of the recently developed Nikkiso centrifugal pump with the well-established Bio-Medicus pump during left heart bypass for thoracoabdominal aortic aneurysm surgery. Thirty-five consecutive patients undergoing graft repair of extensive thoracoabdominal aortic aneurysms were prospectively assigned to have left heart bypass using either the Bio-Medicus (in the first 19 patients) or Nikkiso pump (in the next 16 patients). There were no significant differences in pump flow rates or patient hemodynamics between the two groups and there was no evidence of pump malfunction. All patients survived and none developed postoperative coagulopathy, myocardial infarction, or left heart failure. Paraparesis developed in 2 patients in the Nikkiso group (12.5%); there were no neurologic complications in the Bio-Medicus group (p = 0.202). One patient in the Bio-Medicus group developed renal failure (5.3%; p = 1.000 vs. Nikkiso group). Overall, no significant differences were found in the incidence of postoperative complications. Although a small series, this comparison demonstrates that the Nikkiso centrifugal pump is as effective and safe in providing left heart bypass during thoracoabdominal aortic aneurysm repair as the widely-used Bio-Medicus model.

AbstractSince 1991, in our laboratory, a pivot bearing‐supported, sealless, centrifugal pump has been developed as an implantable ventricular assist device (VAD). For this application, the configuration of the total pump system should be relatively small. The C1E3 pump developed for this purpose was anatomically compatible with the small‐sized patient population. To evaluate an‐tithrombogenicity, ex vivo 2‐week screening studies were conducted instead of studies involving an intracorpore‐ally implanted VADs using calves. Five paracorporeal LVAD studies were performed using calves for longer than 2 weeks. The activated clotting time (ACT) was maintained at approximately 250 s using heparin. All of the devices demonstrated trouble‐free performances over 2 weeks. Among these 5 studies, 3 implantations were subjected to 1‐month system validation studies. There were no device‐induced thrombus formations inside the pump housing, and plasma‐free hemoglobin levels in calves were within the normal range throughout the experiment (35, 34, and 31 days). There were no incidents of system malfunction. Subsequently, the mass production model was fabricated and yielded a normalized index of hemolysis of 0.0014, which was comparable to that of clinically available pumps. The wear life of the impeller bearings was estimated at longer than 8 years. In the next series of in vivo studies, an implantable model of the C1E3 pump will be fabricated for longer term implantation. The pump‐actuator will be implanted inside the body; thus the design calls for substituting plastic for metallic parts.

Abstract: The Nikkiso centrifugal pump was evaluated in elective adult open heard surgery in comparison with the BioMedicus pump. Ten patients using the Nikkiso pump (Group N), and 10 patients using the BioMedicus pump (Group B) were examined for (or to determine) hemato‐biologic parameters and patient outcome data as well as pump controllability. During cardiopulmonary bypass (CPB), both pumps maintained systemic perfusion satisfactorily without any mechanical adverse event. Rotation speed of the Nikkiso centrifugal pump (3,580 ± 100 rpm) was significantly higher than that of the BioMedicus pump (3,170 ± 100 rpm; p < 0.05) whereas changes in free plasma hemoglobin, platelet count, blood urea nitrogen, and creatinine levels showed no significant differences between the two groups. Urine output in Group N for 30 min after the initiation of CPB (7.10 ± 1.50 ml/kg/h) was significantly higher than that in Group B (3.23 ± 0.46 ml/kg/h; p < 0.05). Patient outcome data were similar in both groups, such as duration of intensive care unit stay, hospital stay, postoperative intubation time, amount of postoperative bleeding, and amount of blood transfused. These equivalent results with the BioMedicus pump suggested that the Nikkiso pump can be used in open heart surgery as a reliable and atraumatic CPB pump.

Abstract: The improvement of antithrombogenicity is one of the major objectives for the development of blood pumps. Previously we reported that an in vitro thrombogenic test was useful as a pilot study, especially to predict thrombogenic areas. In this study we modified the method for testing pumps with identical priming volumes by eliminating the blood reservoir. Identical compact mock loops (priming volume of 53 ml. without pump) were constructed and tested with the same priming volume of Nikkiso centrifugal pumps, noncoated verus heparin‐coated. Two pumps were run simultaneously using the same source of fresh heparinized human blood (activated clotting time [ACT] 150–250 s) for 4 or 6 h. Results indicated that the heparin‐coated pump had a longer thrombus free period than the noncoated one. The thrombi location and forms were consistently in the same places the in vivo study had identified. It is suggested that this modified in vitro thrombogenic test is a feasible pilot study, as well as the one previously reported. The minimal priming volume will allow evaluation of multiple pumps simultaneously with the same source blood.

Abstract: A small axial flow ventricular assist device (VAD) measuring 3 inches long and 1 inch in diameter is in development. The pump consists of a spinning inducer/ impeller, a flow straightener (FLS), and a diffuser enclosed in a cylindrical flow tube. The impeller has rod‐shaped permanent magnets embedded within its 6 blades and is activated magnetically by the motor stator which is positioned outside the flow tube. At the completion of a previous study, the FLS was identified as a thrombogenic area. The aim of the present study was to evaluate the thrombogenicity of redesigned FLSs (swept‐back and bulbous types), compared with standard type (STD) FLS. A total of 15 pumps (STD, n = 7; swept‐back, n = 4; and bulbous, n = 4) were sequentially implanted into 4 calves paracorporeally in a short‐term ex vivo test. The STD and bulbous FLSs experienced thrombus formation, but the swept‐back FLS was thrombus free during a 48 h screening test.

Abstract: Current left ventricular assist devices (LVADs) have demonstrated admirable results. However, approximately one‐fourth of the patients who require LVADs suffer from right heart failure and require additional right ventricular (RV) assist devices (RVADs). The RV failure impairs the splanchnic circulation, subsequently developing into multiorgan failure (MOF). An aggressive application of a biventricular assist device (BVAD) is the best way to avoid and treat MOF because the BVAD reduces splanchnic congestion. Also, because the BVAD allows retention of the natural heart, recovery of the heart function can be expected after long‐term assist. This benefit cannot be expected from conventional total artificial hearts. Although there are no implantable clinical BVAD systems in existence today, present advanced technologies in rotary blood pumps can enable these systems to be totally implantable. So, we should focus on developing a totally implantable BVAD system. The implantable BVAD will be a therapeutic and physiological total artificial heart, and it will be a common home health care device in the near future.

Abstract: To be able to salvage heart failure patients, the need for an economical permanent ventricular assist device is increasing. To meet this increasing demand, a miniaturized centrifugal blood pump has been developed as a permanently implantable device. The Gyro permanently implantable model (PI‐601) incorporates a sealless design with a blood stagnation free structure. The pump impeller is magnetically coupled to the driver magnet in a sealless manner. This pump is atraumatic and antithrombogenic and incorporates a double pivot bearing system. A miniaturized actuator was utilized in this system in collaboration with the University of Vienna. The priming volume of this pump is 20 ml. The overall size of the pump actuator package is 53 mm in height and 65 mm in diameter, 145 ml of displacement volume, and 305 g in weight. Testing to date has included in vitro hydraulic performance and hemolysis. This pump can provide 5 L/min against a 110 mm Hg total pressure head at 2,000 rpm and 8 Limin against 150 mm Hg at 2,500 rpm. The normalized index of hemo‐lysis (NIH) value of this pump was 0.0028 g/100 L at 5 Limin against 100 mm Hg. A preliminary anatomical study revealed the possibility of the implantability of 2 such systems in biventricular bypass at a preperitoneal location. This system is feasible for use as a permanently implantable biventricular assist device.

Abstract: During a particular long‐term in vitro hemolysis test, the plasma free hemoglobin suddenly increased even though the hemolysis level had risen linearly for the previous several hours. This phenomenon was dubbed the total destruction of erythrocytes (TDE) phenomenon, and it was hypothesized that this was the result of the accumulation of sublethal damage to erythrocytes. It was suggested that the TDE might demonstrate the hemolytic characteristics of a pump more sensitively than a conventional hemolysis test. However, the previous report did not consider the effects of temperature or contamination. To study these effects, 3 long‐term hemolysis tests were concluded under the following conditions. For Study 1 blood temperature was maintained at 27°C (n = 2); for Study 2, at 37°C (n = 4); and for Study 3, at 37°C with gentamicin (n = 4). The BioMedicus and Nikkiso pumps were used as they were in our previous report. Gas sterilization of all circuits and pumps preceded experimentation. In Studies 1 and 3, hemolysis increased linearly for 29 h. However, in Study 2 a sudden increase of hemolysis occurred for both pumps. Possible causes of this were the dramatic changes in environmental factors such as severe acidosis, high 0, and glucose consumption, and CO2accumulation. In contrast, neither Study 1 nor Study 3 showed a sudden increase in hemolysis. The plasma free hemoglobin increased linearly in both groups until 29 h of pumping. The environmental changes resulting from contamination were considered to be the cause of the sudden increase in hemolysis. In conclusion, the TDE did not reflect mechanical blood cell damage, but rather different environment situations. Hemolysis increased linearly up to 29 h in either 27°C or germ‐free conditions.

Abstract: While a centrifugal pump is generally used for nonpulsatile blood flow, it can also produce a pulsatile flow by alternating the impeller rotational speed (rpm) periodically. However, there is concern that this centrifugal pump pulsatile mode may induce added hemolysis as a result of the repeated acceleration and deceleration of rpm. Thus, a hemolysis study of the pulsatile modes of the Gyro C1E3 centrifugal pump (Gyro‐P) was conducted. The results were then compared with the nonpulsatile mode of the same Gyro pump (Gyro‐N) and the nonpulsatile BioMedicus BP‐80 (Bio‐N) pump. Three different conditions were simulated: left ventricular assist device (LVAD), cardiopulmonary bypass (CPB), and percutaneous cardiopulmonary support (PCPS). The beating rate of the Gyro‐P was set at 40 bpm, with repetition of 2 different impeller speeds (the lower rpm being 70% of the higher speed). The 2 impeller speeds were set to obtain the same average flow as that of the nonpulsatile mode. The hemolysis results of the Gyro‐P were comparable to or better than those of the Bio‐N, and no excessive hemolysis was observed, compared to the Gyro‐N. In conclusion, the Gyro‐P had an excellent hemolytic characteristic and generated no excessive hemolysis in most clinical usage conditions. With the concern of hemolysis eliminated, this pulsatile mode may have various possible advantages.

Successful repair of thrombotic occlusion of the entire inferior vena cava, including the iliac and hepatic veins, was performed on a 51-year-old man with Budd-Chiari syndrome associated with severe liver dysfunction.

A 41-year-old man was diagnosed with anomalous origin of the right coronary artery from the left sinus of Valsalva with a slit ostium. Surgery was offered to the patient in view of his young age and the unpredictable natural history of the disease. Direct reimplantation of the right coronary artery to the right sinus was performed under cardiopulmonary bypass. The patient recovered uneventfully. Postoperative coronary angiography showed good patency of the reconstructed artery while exercise thallium scintigraphy showed no ischemic change. Excellent longevity of the directly reimplanted coronary artery can be expected.

AbstractWe compared in vitro rates of hemolysis for a recently developed centrifugal pump with a conventional roller pump (10‐10‐00; Stöckert, Munich, Germany). Flow rates of 0.3 L/min and 1 L/min and a pressure of 200 mm Hg were chosen to simulate conditions during neonatal extracorporeal membrane oxygenation (ECMO). There was no significant difference in hemolysis rates between centrifugal and roller pumps (p = 0.57) nor between high and low flow (p = 0.86). The centrifugal pump caused no more blood trauma than the roller pump at the low‐flow/high‐pressure conditions required for neonatal ECMO. The Nikkiso pump is superior to roller pumps in size and priming volume (25 ml) and may permit development of a smaller and simpler ECMO system.